Typically, a switching power supply circuit includes a comparison circuit, an oscillation circuit and a booster circuit. The comparison circuit compares an output voltage of the booster circuit with a reference voltage and actuates the oscillation circuit when the output voltage becomes lower than the reference voltage. The oscillation circuit generates an oscillation signal and supplies this oscillation signal to the booster circuit. The booster circuit has its internal switch turned ON/OFF in accordance with the oscillation signal and generates an output voltage higher than the input voltage. When the output voltage of the booster circuit becomes higher than the reference voltage, the comparison circuit stops the oscillation circuit. By this negative feedback control, the output voltage of the booster circuit becomes closer to the reference voltage.
The power consumption by the comparison circuit can be reduced by operating the comparison circuit intermittently instead of operating it at all times. However, if a new signal source is added for generating an operation control signal that causes the comparison circuit to operate intermittently, the increase of power consumption caused by the addition of the new signal source becomes a problem.